For example, analysis of an aroma of leaf tobacco is performed by collecting constituents evaporating from the leaf tobacco (laminae or shreds) and analyzing the collected volatile constituents. Further, if flour or the like has abnormal smell, analysis of the abnormal smell of the flour or the like is performed by collecting constituents evaporating and escaping from the flour or the like and analyzing the collected constituents.
A conventional and common way of collecting volatile constituents from a solid is, for example, as shown in FIG. 10, to put a sample S of leaf tobacco or the like in a hermetic container 1 such as a sample vessel, heat it with a heater 2, and collect constituents G which evaporate from the sample S due to the heating and accumulate in an upper space of the hermetic container 1 (a static method; a head space method). Another conventional and common way is, as shown in FIG. 11, to heat a sample S in a hermetic container 3 with a heater 4, and collect constituents G evaporating from the sample S with a collecting agent 6 provided in a collecting tube 5 while the constituents G are continuously circulated between the hermetic container and the collecting tube 5 (a dynamic method).
However, when constituents G evaporating from a sample S are collected in the above-described manners, the respective amounts of the constituents (quantitative relation between the constituents) change under some conditions about heating of the sample S. For example, when heated, constituents contained in a sample S may be thermally decomposed and produce unexpected secondary products. Further, constituents G which evaporate from the sample S vary in volatility, from a high volatility to a low volatility. For example, pressure of a constituent G which is high in volatility and evaporates from the sample S in the hermetic container 1 earliest (inner pressure) may prevent a constituent G which is low in volatility from evaporating from the sample S and make it difficult to collect the latter constituent G. Thus, it is difficult to ensure the collection of volatile constituents which are different in volatility and then to analyze them accurately.
An object of this invention is to provide a method and apparatus for ensuring the extracting and collecting of volatile constituents contained in a solid sample such as leaf tobacco or flour. It is then an object of this invention to perform an analysis on the collected constituents using either an atmospheric concentration technique or a sensory evaluation, i.e. human sense of smell.
In order to achieve the above object, the invention is characterized in that a sample of a solid containing volatile constituents is put in a hermetic sample vessel (hermetic can) with inert gas, and a canister, depressurized in advance, is selectively connected to the sample vessel so that the sample vessel will be depressurized in a moment and constituents evaporating from the sample will be collected into the canister. Thus, the volatile constituents can be extracted from the sample without heating the sample.
Specifically, an apparatus for extracting volatile constituents according to the present invention comprises a sample vessel for containing a sample containing volatile constituents, a gas feeding device for filling the sample vessel containing the sample with inert gas, a thermostatic chamber for containing the sample vessel and keeping the sample contained in the sample vessel at a predetermined temperature (a temperature at which thermal decomposition does not happen, for example, an ordinary temperature), and a canister as a collecting container capable of being depressurized in advance and selectively connected to the sample vessel for collecting constituents evaporating from the sample contained in the sample vessel.
Desirably, the gas feeding device is designed to fill the sample vessel with inert air to replace atmospheric air in the sample vessel containing the sample by the inert gas. The canister is desirably designed to be depressurized to about 1×102 Pa in advance and selectively connected to the sample vessel to collect constituents evaporating from the sample under depressurization, by sucking the constituents with negative pressure in a canister.
A method of extracting volatile constituents according to the present invention comprises the steps of putting a sample containing volatile constituents in a sample vessel, then filling the sample vessel containing the sample with inert gas and keeping the sample at a predetermined temperature (a temperature at which the volatile constituents do not evaporate through thermal decomposition of the sample, for example, an ordinary temperature), and thereafter selectively connecting a canister depressurized in advance to the sample vessel to thereby collect constituents evaporating from the sample under depressurization, into the canister with the inert gas in a moment.
When volatile constituents of the sample are collected into the canister in the above-described way in particular, not only chemical analysis of the volatile constituents with an atmospheric concentration analyzer but also sensory evaluation of the volatile constituents with a human sense of smell can be performed effectively. Further, the volatile constituents can be evaluated as a whole, analytic-chemically as well as sensory-scientifically, irrespective of when the volatile constituents were collected into the canister.